The paranasal sinuses are hollow cavities in the skull connected by small openings, known as ostia, to the nasal canal. Each ostium between a paranasal sinus and the nasal cavity is formed by a bone covered by a layer of mucosal tissue. Normally, air passes into and out of the paranasal sinuses through the ostia. Also, mucus is continually formed by the mucosal lining of the sinuses and drains through the ostia and into the nasal canal.
Sinusitis is a general term that refers to inflammation in one or more of the paranasal sinuses. Acute sinusitis can be associated with upper respiratory infections or allergic conditions, which may cause tissue swelling and temporarily impede normal trans-ostial drainage and ventilation of the sinuses, thereby resulting in some collection of mucus and possibly infection within the sinus cavities. Chronic sinusitis is a long term condition characterized by persistent narrowing or blockage of one or more sinus ostia, resulting in chronic infection and inflammation of the sinuses. Chronic sinusitis is often associated with longstanding respiratory allergies, nasal polyps, hypertrophic nasal turbinates and/or deviated internasal septum. While acute sinusitis is typically caused by infection with a single pathogen (e.g., one type of bacteria, one type of virus, one type of fungus, etc.), chronic sinusitis is often associated with multiple pathogen infections (e.g., more than one type of bacteria or more than one genus of micro-organism).
Chronic sinusitis, if left untreated, can result in irreparable damage to the tissues and/or bony structures of the paranasal anatomy. The initial treatment of chronic sinusitis usually involves the use of drugs such as decongestants, steroid nasal sprays and antibiotics (if the infection is bacterial). In cases where drug treatment alone fails to provide permanent relief, surgical intervention may be indicated.
The most common surgical procedure for treating chronic sinusitis is functional endoscopic sinus surgery (FESS). FESS is commonly performed using an endoscope and various rigid instruments inserted through the patient's nostril. The endoscope is used to visualize the positioning and use of various rigid instruments used for removing tissue from the nasal cavity and sinus ostia in an attempt to improve sinus drainage.
A technique known as the Balloon Sinuplasty™ procedure and a system for performing the procedure have been developed by Acclarent Inc, of Menlo Park, Calif. for treatment of sinusitis. A number of US patents and patent applications including U.S. Pat. Nos. 7,645,272, 7,654,997, and 7,803,150 and Publications 2008/0097154 and 2008/0281156 each of which is hereby incorporated in full by reference, describe various embodiments of the Balloon Sinuplasty™ procedure as well as various devices useable in the performance of such procedure. In the Balloon Sinuplasty™ procedure, a guide catheter is inserted into the nose and positioned within or adjacent to the ostium of the affected paranasal sinus. A guidewire is then advanced through the guide catheter and into the affected paranasal sinus. Thereafter, a dilation catheter having an expandable dilator (e.g. an inflatable balloon) is advanced over the guidewire to a position where the dilator is positioned within the ostium of the affected paranasal sinus. The dilator is then expanded, causing dilation of the ostium and remodelling of bone adjacent to the ostium, without required incision of the mucosa or removal of any bone. The catheters and guidewire are then removed and the dilated ostium allows for improved drainage from and ventilation of the affected paranasal sinus. There is a continuing need for improved methods and devices for treating the paranasal sinus.
The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings, in which like numerals indicate like elements.